Cooling circuit apparatus and method

ABSTRACT

A cooling circuit through which coolant flows, for use with a refrigerated cabinet. The cooling circuit includes a compressor and a condenser with a flow path extending there between. The cooling circuit also includes an evaporator and a second flow path that extends between the evaporator and the condenser. The cooling circuit additionally includes a suction accumulator and a flow path extending between the evaporator and the suction accumulator, while a fourth flow path extends between the suction accumulator and the compressor. The cooling circuit also includes a coolant bypass and a switch that switches the cooling circuit between a cycling mode and a non-cycling mode.

This application is a Continuation of U.S. patent application Ser. No.10/727,600, filed Dec. 5, 2003, entitled COOLING CIRCUIT APPARATUS ANDMETHOD, now U.S. Pat. No. 6,845,632, the disclosure of which isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to the field of refrigeratedcabinets. More particularly, the present invention relates to anapparatus and method for providing a cooling circuit for use with arefrigerated cabinet, such as a refrigerator and/or freezer, thatefficiently maintains a precise or stable refrigerated cabinettemperature, thereby reducing air pressure fluctuations within theinterior of the refrigerated cabinet.

BACKGROUND OF THE INVENTION

Currently, refrigerated cabinets such as refrigerators and/or freezers,generally employ a single vapor-compression circuit to cool or maintainthe temperature of the refrigerated cabinet. Typically, therefrigeration circuit uses a refrigerant or coolant gas which is cycledthrough the refrigeration circuit. During the cooling process, therefrigerant or coolant gas is compressed in a compressor unit causingthe coolant to become hot. The heat generated by the aforementionedcompression is then removed generally by passing the compressed gasthrough a water or air cooled condenser coil. The cooled, condensedliquid is then allowed to rapidly expand into an evaporating coil wherethe expanded gas becomes much colder, thus cooling the coil and thecabinet around which, or within which, the evaporating coil is placed.

Refrigerated cabinets employing vapor-compression circuits or systemssimilar to the circuit or system described above, are typically designedto cycle the vapor-compression circuit or system on and off in order tohold or maintain the cabinet temperature at a desired setting.Oftentimes, the aforementioned on and off cycling of thevapor-compression circuit or system may cause strain on the system'smechanical components such as the compressor. This cycling may alsocause temperature fluctuations within the cabinet, and hence, airpressure fluctuations, within the cabinet. These temperaturefluctuations often times cause undesired frost formation within thecabinet due to the pressure differential between the interior of therefrigerated cabinet and the outside environment, as a result of thevarying cabinet air temperatures.

One current method for reducing the likelihood of the above-describedtemperature fluctuations includes adding a liquid refrigeration bypasscircuit to the vapor-compression circuit. The bypass circuit allows fora portion of the liquid refrigerant or coolant to circumvent or bypassthe evaporator, thus modulating the refrigerant or coolant flow capacityinto the evaporator. This modulation of the flow of the liquidrefrigerant or coolant into the evaporator causes the interiorrefrigerated cabinet temperature to be more stable thereby causing theair pressure within the cabinet to be more stable. Moreover, theaforementioned method allows for the compressor to run continuously andnot cycle on and off.

The aforementioned method for addressing temperature fluctuation withrefrigerated cabinets has drawbacks however. Due to the bypass circuit,the compressor runs constantly, causing the refrigerated cabinet toconsume more energy than a refrigerated cabinet that employs acompressor that cycles on and off. Moreover, due to the constantoperation of the compressor, operational noise levels of therefrigerated cabinet are increased.

Accordingly, there is a need in the art to provide a cooling circuitapparatus and method for use with refrigerated cabinets and the like,that allows for efficient, precise temperature control. Also, there is afurther need for a cooling circuit apparatus and method for use withrefrigerated cabinets that have a refrigerant or coolant bypass featurethat may be activated and inactivated as desired.

SUMMARY OF THE INVENTION

The foregoing needs are met, to a great extent, by the presentinvention, wherein in one aspect, a cooling circuit for use with arefrigerated cabinet is provided. The cooling circuit includes acompressor and a condenser, wherein a first flow path extends betweenthe compressor and the condenser. The cooling circuit also includes anevaporator, wherein a second flow path extends between the condenser andthe evaporator. The cooling circuit additionally includes a suctionaccumulator and a third flow path that extends between the evaporatorand the suction accumulator. A fourth flow path extends between thesuction accumulator and the compressor. The cooling circuit furtherincludes a coolant bypass that extends between the second flow path andthe third flow path. The coolant bypass includes a fifth flow path and aflow control valve. Finally, the cooling circuit includes a switch thatswitches the cooling circuit between a cycling mode and a non-cyclingmode.

In accordance with another embodiment of the present invention, acooling circuit through which coolant flows, for use with a refrigeratedcabinet is provided. The cooling circuit includes a compressor and acondenser, wherein a first flow path extends between the compressor andthe condenser. The cooling circuit also includes an evaporator, whereina second flow path extends between the condenser and the evaporator. Thecooling circuit additionally includes a suction accumulator and a thirdflow path that extends between the evaporator and the suctionaccumulator. A fourth flow path extends between the suction accumulatorand the compressor. The cooling circuit further includes a coolantbypass that extends between the first flow path and the second flowpath. The coolant bypass includes a fifth flow path and a flow controlvalve. Finally, the cooling circuit includes a switch that switches thecooling circuit between a cycling mode and a non-cycling mode.

In accordance with still another embodiment of the present invention, acooling circuit through which coolant flows, for use with a refrigeratedcabinet is provided, comprising: means for providing a cooling circuitthrough which coolant flows, comprising: a compressor; a condenser,wherein a first flow path extends between a said compressor and saidcondenser; an evaporator, wherein a second flow path extends betweensaid condenser and said evaporator; a suction accumulator, wherein athird flow path extends between said evaporator and said suctionaccumulator and wherein a fourth flow path extends between said suctionaccumulator and said compressor; a coolant bypass that extends betweensaid second flow path and said first flow path, wherein said coolantbypass comprises a fifth flow path and a flow control valve; and aswitch that switches the cooling circuit between a cycling mode and anon-cycling mode; means for selecting a desired air temperature for therefrigerated cabinet; and means for selecting an operating mode from thecycling mode and the continuous mode using the switch.

In accordance with yet another embodiment of the present invention, amethod for cooling a refrigerated cabinet, comprising the steps of:providing a cooling circuit through which coolant flows, comprising: acompressor; a condenser, wherein a first flow path extends between saidcompressor and said condenser; an evaporator, wherein a second flow pathextends between said condenser and said evaporator; a suctionaccumulator, wherein a third flow path extends between said evaporatorand said suction accumulator and wherein a fourth flow path extendsbetween said suction accumulator and said compressor; a coolant bypassthat extends between said second flow path and said first flow path,wherein said coolant bypass comprises a fifth flow path and a flowcontrol valve; and a switch that switches the cooling circuit between acycling mode and a non-cycling mode; selecting a desired air temperaturefor the refrigerated cabinet; and selecting an operating mode from thecycling mode and the non-cycling mode using the switch.

There has thus been outlined, rather broadly, certain embodiments of theinvention in order that the detailed description thereof herein may bebetter understood, and in order that the present contribution to the artmay be better appreciated. There are, of course, additional embodimentsof the invention that will be described below and which will form thesubject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of embodiments inaddition to those described and of being practiced and carried out invarious ways. Also, it is to be understood that the phraseology andterminology employed herein, as well as the abstract, are for thepurpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conceptionupon which this disclosure is based may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a cooling circuit apparatus for use with arefrigerated cabinet in accordance with an embodiment of the presentinvention.

FIG. 2 is a schematic view of a cooling circuit apparatus for use with arefrigerated cabinet in accordance with an embodiment of the presentinvention.

FIG. 3 is a schematic view of a cooling circuit apparatus for use with arefrigerated cabinet in accordance with an alternative embodiment of thepresent invention.

FIG. 4 is a schematic view of a cooling circuit apparatus for use with arefrigerated cabinet in accordance with an alternative embodiment of thepresent invention.

DETAILED DESCRIPTION

Various preferred embodiments of the present invention provide for acooling circuit apparatus and method for use with a refrigeratedcabinet. The cooling circuit apparatus and method provides the benefitsof both a cycling and non-cycling compressor system in a single unit. Insome arrangements, the cycling mode of the cooling circuit apparatus andmethod is utilized while in other arrangements the non-cycling mode ofthe cooling circuit apparatus and method is utilized. It should beunderstood, however, that the present invention is not limited in itsapplication to refrigerated cabinets, but, for example, can be used withother temperature control cabinets or apparatuses that require precisetemperature and/or precise air pressure control. Preferred embodimentsof the invention will now be further described with reference to thedrawing figures, in which like reference numerals refer to like parts.

Referring now to the figures, FIGS. 1–4 illustrate a cooling circuitapparatus, generally designated 10, for use with a refrigerated cabinetin accordance with an embodiment of the present invention. The coolingcircuit apparatus 10 includes a compressor 12 that is connected to acondenser 14 via a conduit or tubing section 15, and a first expansiondevice 16. The condenser 14 and the first expansion device 16 areconnected via a conduit or tubing section 18. The cooling circuitapparatus 10 also includes an evaporator 20 that is connected to thefirst expansion device 16 by way of a conduit or tubing section 22. Theevaporator 20 is also connected to a suction accumulator 24 through aconduit or tubing section 26. As illustrated in FIGS. 1–4, the suctionaccumulator 24 connects to the compressor 12 via a conduit or tubing 28to complete the cooling circuit 10.

As depicted in FIGS. 1–4, the cooling circuit apparatus 10 additionallyincludes a coolant bypass, generally designated by reference numeral 30,a selectable toggle switch 32 and a controller 33. The selectable toggleswitch 32 functions to switch the cooling circuit 10 between a cyclingmode and a non-cycling mode. The controller 33 is a standard controllerknown in the art, utilized to control and maintain the temperature ofrefrigerated cabinets and the like. The controller 33 receives inputsfrom a temperature sensor 35 which communicates with the controller 35.The temperature sensor 35 can be positioned at varying locations alongthe cooling circuit apparatus 10. The temperature sensor 35 sends inputsto the controller 33 and in response to these inputs, the controller 33activates or deactivates the coolant bypass 30. The selectable toggleswitch 32 preferably switches the operation of the cooling circuitapparatus 10 between a compressor cycling mode and a compressornon-cycling mode.

In embodiments depicted in FIGS. 1 and 2, the coolant bypass 30 extendsbetween conduit section 18 and conduit section 26, while in theembodiments depicted in FIGS. 3 and 4 the coolant bypass 30 extendsbetween conduit section 22 and conduit section 16. The coolant bypass 30includes a flow control valve 34, for example, a solenoid valve 34 and asecond expansion device 36. The solenoid valve 34 can be activate andinactivated by the controller. As illustrated in FIGS. 1–4, the coolantbypass 30 includes conduit or tubing sections 38, similar to thosepreviously described, that combine to form the coolant bypass 30.

In the embodiment illustrated in FIGS. 1 and 2, the coolant bypass 30reduces the amount of coolant flow that enters the evaporator 20, orenables the coolant flow to bypass the evaporator 20, when the coolantbypass 30 is activated. Alternatively, in the alternative embodimentdepicted in FIGS. 3 and 4, the coolant bypass 30 reduces the amount ofcoolant that enters the condenser 14, or enable the coolant flow tobypass the condenser, when activated.

As depicted in FIGS. 1–4, the compressor 12 is preferably any standardcompressor known in the art that compresses gas or vapor. The compressor12 functions to compress coolant vapor and/or a coolant vapor/liquidmixture that it receives from the suction accumulator 24. Thiscompression causes the coolant to become extremely hot. The compressor12 also functions to propel the coolant through the cooling circuitapparatus 10. The compressor 12 is connected to the evaporator 16 by theconduit or tubing section 16. The conduit or tubing section 16 ispreferably refrigeration conduit, and may be constructed from anymaterial suitable for refrigeration, for example stainless steel orcopper, however alternative materials may be utilized.

As illustrated in FIGS. 1–4, the condenser 14 is preferably any standardcondenser known in the art. For example, the condenser 14 may be a watercooled condenser and/or an air cooled condenser. The condenser 14functions to remove some of the heat contained in the hot compressedcoolant. The condenser 14 is connected to both the cooling bypass 30 andthe first expansion device 16 via the conduit or tubing section 18. Theconduit or tubing section 18 is preferably refrigeration conduit, andmay be constructed from any material suitable for refrigeration, such asstainless steel or copper, however alternative materials may beutilized.

The first expansion device 16 is preferably a metering device orpressure reducing valve such as a thermal expansion valve, a capillarytube and/or a needle valve. The first expansion device functions tomodulate or control the flow of coolant into the evaporator 20. Asdepicted in FIGS. 1–4, the first expansion device 16 is connected to theevaporator 20 by the conduit or tubing section 22. The conduit or tubingsection 22 is preferably refrigeration conduit, and may be constructedfrom any material suitable for refrigeration, such as stainless steel orcopper, however alternative materials may be utilized if desired.

The evaporator 20 is preferably any standard evaporator known in theart, such as a static cold wall evaporator or a forced air evaporator.The evaporator 20 functions to remove heat from the environment withinwhich or around which, the evaporator is located. The evaporator 20, asillustrated in FIGS. 1–4, is connected to the suction accumulator 24 bythe conduit or tubing section 26. The conduit or tubing section 26 ispreferably refrigeration conduit, and may be constructed from anymaterial suitable for refrigeration, such as stainless steel or copper,however alternative materials may be utilized.

As illustrated in the figures, the suction accumulator 24 is locatedbetween evaporator 20 and the condenser 12 and is essentially a vesselor container that functions to collect or accumulate any residualcoolant fluid the exits the evaporator 20. The suction accumulatoradditionally functions to allow coolant vapor that exits the evaporator20 to pass onto the condenser 12. The suction accumulator 24 preferablyincludes a return (not pictured) that can be connected to either thecompressor 12 or the conduit section 28. The return allows a minimalamount of liquid coolant that has collected in the suction accumulator,to mix with coolant vapor and return to the compressor 12 to becompressed. The suction accumulator 24 is connected to the compressor 12via the conduit or tubing section 28. The conduit or tubing section 28is preferably refrigeration conduit, and may be constructed from anymaterial suitable for refrigeration, such as stainless steel or copper,however alternative materials may be utilized.

Referring now to FIGS. 1 and 2 and the embodiment illustrated therein,as previously mentioned, the bypass 30 extends between conduit section18 and conduit section 26 and enables a majority of the coolant tobypass the first expansion device 16 and evaporator 20. As illustratedin FIGS. 1 and 2, the coolant bypass 30 includes a solenoid valve 34that controls the flow of coolant through the coolant bypass 30. Thecoolant bypass 30 also includes a second expansion device 36. The secondexpansion device 36 is similar to the first expansion device 16 in thatit is preferably a metering device or pressure reducing valve such as athermal expansion valve, a capillary tube and/or a needle valve. Thesecond expansion device 36 however differs from the first expansiondevice 16 because it is less restrictive than the first expansion device16. By less restrictive it is understood that the second expansiondevice 36 applies lesser resistance to the flow of coolant, andtherefore the coolant flows through the second expansion device 36 moreeasily. Therefore, when the solenoid valve 34 is activated, a majorityof coolant will follow the path of lowest resistance and flow throughthe coolant bypass 30.

Continuing to refer to FIGS. 1 and 2, the cooling circuit apparatus 10is depicted in the continuous run position or non-cycling compressormode. By continuous run position or non-cycling compressor mode, it isunderstood that the end user desires to achieve full cooling andmaintain a stable interior cabinet air temperature and air pressure. Inthis position, the selectable toggle switch 32 is set to a firstposition, where in this first position, the compressor 12 runscontinuously. Also, while in this first position, the solenoid valve 34is initially deactivated while the cooling circuit operates to achievethe desired set temperature.

During operation of the cooling circuit apparatus 10 in the continuousrun position, the end user first selects a desired temperature via thecontroller 33. During operation, the coolant vapor is compressed in thecompressor 12 and it then flows to the condenser 14 through conduit 16,as indicated by the arrows 40. As previously described, at the condenser14, some of the heat is removed from the coolant and the coolant iscondensed. The coolant then proceeds to flow through conduit section 18and on through the first expansion device 16 as indicated by arrows 42.As previously mentioned, the solenoid valve 34 is closed at this stageof the continuous run position and therefore all of the coolant proceedsto flow into the evaporator 20, providing full cooling to the to theinterior environment to the refrigerated cabinet. The coolant thenproceeds through the conduit section 26 to the suction accumulator 24,as indicated by the arrow 46, where it then proceeds to return to thecompressor 12.

Referring now to FIG. 2, once the desired interior cabinet temperatureis obtained, the controller 33 activates the solenoid valve 34 allowingcoolant to flow through the coolant bypass 30 as illustrated. Asdiscussed above, the second expansion device 36 is less restrictive thanthe first expansion device 16 and therefore a majority of the coolantflows through the coolant bypass, bypassing the evaporator 20.

Due to the aforementioned flow of coolant through the bypass 30, theamount of coolant that enters the evaporator 20 is significantlyreduced, thus causing the temperature of evaporator 20 to rise.Meanwhile, the liquid coolant flowing through the coolant bypass 30flows through the solenoid valve 34 and second expansion device 36 andinto the suction accumulator 24 as indicated by arrows 46. Once thecoolant enters the suction accumulator 24, it mixes with the incomingcoolant flow from the evaporator 20. Due to the coolant bypass 30 andthe aforementioned mixing of the coolant, the combined coolant vaporthat enters the compressor is cold and beneficial to compressor 12longevity.

Referring now to FIGS. 3 and 4 in this embodiment, once the desiredinterior cabinet temperature is obtained, as described above, thecontroller 33 again activates the solenoid valve 34, allowing coolant toflow through the coolant bypass 30 as illustrated in FIG. 4. Again, thesecond expansion device 36 is less restrictive that first expansiondevice therefore a majority of the coolant flows through the coolantbypass 30, bypassing the condenser 14.

The cooling circuit apparatus 10 configuration illustrated in FIG. 4allows for a portion of hot, non-condensed coolant gas to flow throughthe bypass 30, including the solenoid valve 34 and second expansiondevice 36, directly into the evaporator 20. This hot, non-condensedcoolant gas then mixes with the residual liquid coolant that flowedthrough the condenser 14, in the evaporator 20. This mixture of hot gascoolant and liquid coolant causes the evaporator temperature to rise,similar to the embodiment depicted in FIGS. 1 and 2.

Once the internal cabinet temperature begins to rise, the controller 33de-activates the solenoid valve 34 in both embodiments, quicklyreturning the cooling circuit 10 to full capacity as depicted in FIGS. 1and 3. The above-described continuous run position of the coolingcircuit 10 for both embodiments provides a refrigerated cabinet that isable to maintain a stable and precise interior cabinet air temperatureand therefore a stable air pressure, thereby reducing the likelihood ofmoisture infiltration into the refrigerated cabinet.

Alternatively, when the selectable toggle switch 32 is switched to asecond position, the cooling circuit 10 operates in a cycling mode. Inthe cycling mode, the coolant bypass 30 is disengaged and the compressorcycles on and off in accordance with the temperature settings of thecontroller 33.

The many features and advantages of the invention are apparent from thedetailed specification; and thus, it is intended by the appended claimsto cover all such features and advantages of the invention which fallwithin the true spirit and scope of the invention. Further, sincenumerous modifications and variations will readily occur to thoseskilled in the art, it is not desired to limit the invention to theexact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the invention.

1. A cooling circuit through which coolant flows, for use with arefrigerated cabinet, comprising: a compressor; a condenser, wherein afirst flow path extends between said compressor and said condenser; anevaporator, wherein a second flow path extends between said condenserand said evaporator; a suction accumulator, wherein a third flow pathextends between said evaporator and said suction accumulator and whereina fourth flow path extends between said suction accumulator and saidcompressor; a coolant bypass that extends between said first flow pathand said second flow path, wherein said coolant bypass comprises a fifthflow path and a flow control valve; and a switch that switches thecooling circuit between a cycling mode and a non-cycling mode.
 2. Thecooling circuit according to claim 1, further comprising: a firstexpansion device disposed on said second pathway; and a second expansiondevice disposed said fifth pathway.
 3. The cooling circuit according toclaim 1, further comprising: a temperature sensor operable to sense atemperature at a certain location of the cooling circuit; and a controloperable to control flow of coolant through the cooling circuit andthrough said coolant bypass in response to the temperature sensed bysaid sensor.
 4. The cooling circuit according to claim 1, wherein saidfirst, second, third, fourth and fifth flow paths are refrigerationconduits.
 5. The cooling circuit according to claim 4, wherein saidrefrigeration conduits are copper and/or stainless steel.
 6. The coolingcircuit according to claim 1, wherein said flow control valve is asolenoid valve.
 7. The cooling circuit according to claim 1, whereinsaid first and said second expansion devices are a metering deviceand/or a pressure reducing valve.
 8. The cooling circuit according toclaim 7, wherein said metering device and pressure reducing valveinclude a thermal expansion valve, a capillary tube and/or a needlevalve.
 9. The cooling circuit according to claim 1, wherein saidcondenser is a water cooled condenser and/or an air cooled condenser.10. The cooling circuit according to claim 1, wherein said evaporator isa static cold wall evaporator and/or a forced air evaporator.
 11. Acooling circuit through which coolant flows, for use with a refrigeratedcabinet, comprising: means for providing a cooling circuit through whichcoolant flows, comprising: a compressor; a condenser, wherein a firstflow path extends between a said compressor and said condenser; anevaporator, wherein a second flow path extends between said condenserand said evaporator; a suction accumulator, wherein a third flow pathextends between said evaporator and said suction accumulator and whereina fourth flow path extends between said suction accumulator and saidcompressor; a coolant bypass that extends between said second flow pathand said first flow path, wherein said coolant bypass comprises a fifthflow path and a flow control valve; and a switch that switches thecooling circuit between a cycling mode and a non-cycling mode; means forselecting a desired air temperature for the refrigerated cabinet; andmeans for selecting an operating mode from the cycling mode and thecontinuous mode using the switch.